Method of and apparatus for taking motion pictures



Sept. R HOLST METHOD OF AND APPARATUS FOR TAKING MOTION PICTURES FiledMay .16, 1930 2 Sheets-Sheet l Sept. 29, 1936.

1.. J. R. HOLST 2,055,492 METHOD OF AND APPARATUS FOR TAKING MOTIONPICTURES Filed May 16, 1930 2 Sheets-Sheet 2 43" 6!- 47 W ,7 s 50' 460)I, q I d I? R? 4 III/ 4La/ 71 7 Iwenim IOdead 39126;

Patented .Sept. 29, 1936 UNITED STATES PATENT OFFICE METHOD OF ANDAPPARATUS FOR TAKING MOTION PIQTURES I Application May 16,

' 4 Claims.

My invention is amethod of and apparatus for producing chronophotographsby which actual uninterrupted continuous movements may be recorded asobserved in looking at a scene instead 5 of recording a series ofquickly succeeding stationary images of positions reached after statedtime intervals. My improvements result in the production of a film orimage strip which, when properly projected, will show upon a screencomp'letely natural changes in position of all moving objects in thescene and creates such a compelling mental impression as to giveincreased naturalness to even non-moving parts of the scene.

The film or image strip may also have formed thereon a photographiclight record of sounds complementary to the adjacent images, and anyeffect of camera noise on the sound record may be eliminated by placingthe sound recording instrument in any desired position away from thecamera. By recording the light record of complementary sounds on thefilm as it passes the image gate, or immediately before or after this-moment, the scene records and complementary sound records may be placedin or close to transverse coincidence to each other.

My improvements further provide improved means for feeding a sensitizedstrip to and from position for exposure to desired light rays, forrewinding the film without removing it from the camera, and forautomatically opening communication between the film magazine and camerawhen positioned for use and sealing the film magazine when removed fromthe camera.

In accordance with my invention a sensitized film strip is movedcontinuously and preferably at a uniform rate past an image gate whichmay approximate in size the image of a scene to be recorded upon thefilm. I Instead, however, of simultaneously recording the whole of animsupplementary gate forming a narrow slot which passes at any one timethe light rays from a fragmentary portion only-of the image beingrecorded and by the adjustment of the height of the exposure slot theexposure period may be regulated.

The film section while subject to the action of the light rays liesadjacent to and preferably in the image focal plane of an image-forminglens which produces in such plane a replica of an aerial image formed bya photographic lens having its posterior or image focal plane coincidentwith the anterior or objective focal plane of the supplementary orauxiliary lens above 55 referred to. The light rays acting upon the age,there is preferably provided an adjustable 1930, Serial No. 452,871

exposed film section are displaced laterally in. synchronism with and atthe same rate as the movement of the film so that when a narrow exposureslot is used there is imprinted upon the film sequential fragmentaryportions of the image of the scene within the focus of the photo- 5graphic lens. As the film advances across the slot and portions of theimage are impressed thereon, there is produced on the film a series ofphotographs which when properly projected upon a screen give an accurateand exact reproduction of the movements in the original scene. Thedeflection of the light rays in synchronism with the movement of thefilm is effected by means of a rotatable prism positioned in the axis ofthe lenses and preferably in the image space of the supplementary lens.By thus positioning the prism, a prism of practical size may be used.Moreover, the rays passing through a prism located in the image space ofa lens are converging and hence there is obviated the dimming of relatedimage sections which tends to result where parallel or diverging raysare passed through a prism block, and which latter results in failure ofpart of the light rays to penetrate the prism block and their reflectionback from prism surfaces when the angle of incidence of the rays withsteeply inclined prism surfaces is sufiiciently large. When convergingbeams, instead of diverging or parallel beams, of light are caused totraverse a prism, the angles of incidence of the light beams aregreatest when the prism presents its surfaces normal to the optical axisand gradually decrease until the line of separation between two prismsurfaces is in the 35 horizontal plane of the optical axis, henceasubstantially constant amount of light is passed through the prism andthe rays thereof are bent at a rate proportionate to the rate orrotation of the prism.

Films so produced, or prints made therefrom, are preferably exhibited bythe continuous movement thereof through a projector having optical partssimilar to those employed in my camera and through which light rayspassing from an image on the film are focused by an auxiliary lens toform an aerial image in the objective focal plane of a projecting lens,the rays being displaced during their passage to compensate for thecontinuous movement of the film. It will generally be preferable intaking pictures to have the sensitized film surface coincident with theimage focal plane of the supplementary lens and thereby produce sharplydefined images on the film suitable for exhibition in standardprolustrating a preferred embodiment of my improvements; Fig. 2 is atransverse sectional View on the line 2-2 of Fig. 1; Fig. 3 is anenlarged fragmentary sectional view illustrating details of drivingmechanism; Fig. 4 is an enlarged fragmentary sectional view of the filmslot control mechanism applicable to the several embodiments of myinvention; Fig. 5 is a diagrammatic longitudinal sectional view of amodified form ofcamera; Fig. 6 is a transverse sectional view of theline B6 of Fig. 5; Fig. 7 is a diagrammatic fragmentary longitudinalsectional view of a further modified arrangement of the optical elementsof the camera shown in Fig; 5; Fig. 8 is an enlarged fragmentary viewillustrating details of gate and sound recording mechanism applicable tothe several embodiments of my invention illustrated by the previousfigures; and Fig. 9 is a transverse sectional view of the mechanismshown in Fig. 7.

As illustrated in Figs. 1 to 4 inclusive of the.

drawings, the camera housing or casing i is divided by partitions 2, 3,and 6 into chambers 5, 6, l, and 8. A photographic lens 9 is mounted ina tube i9 sleeved in thevcylindrical barrel ll seated in the front wallof-the chamber 5 and secured thereto by a fiange l2. The lens tube ID isadjustable to focus the lens 9 by means of a pin l3 fixed thereto andmovable in an inclined slot i l in the barrel i i. By proper adjustmentof the focus of the lens, an aerial image is formed. substantially inthe plane of the adjustable gate leaves i5 controlling an aperture i6through the partition 2.

An adjustable auxiliary lens ll is mounted in the chamber 6 with itsfront focal plane coincident with the posterior focal plane of the lens9, and the diverging rays from the image formed in the plane of the gateleaves B5 are caused by passage through the lens ill to converge in a.focal plane substantially coincident with the plane of a sensitizedstrip of film is in its passage past the slot l9 (Fig.3) of theadjustable gate leaves i9 which control the image gate or aperture 20 inthe partition 3.

' Shafts 2i, journalled in suitable brackets or in the camera housinghave fixed thereto cheek plates engaging between them a twelve sidedprism block of optical glass 22 disposed in the optical axis of the lensI1 and preferably positioned between such lens and the gate l9, so thatconverging rays passing from thelens I! to the gate iii are displaced bythe rotation of the prism block 22 in synchronism with and in proportionto the movement of the sensitized strip i8 past the slot IS.

The synchronous movement of the prism block and sensitized strip may beefiected by means of a shaft 23 journalled in the camera and providedwith a crank or handle Zi. The shaft 23 has fixed thereto a worm 25which meshes with a worm wheel 26 fixed on a shaft 2! of the prism block22. A second worm Z1, fixed to the shaft 23, meshes with a worm wheel 28fixed to the shaft 29. A sprocket 30 is fixed to the shaft 29 andsprocket 3| is loosely sleeved on the shaft 29 coaxially with thesprocket all. A gear wheel 32 25 and 26 to rotate the prism 22; actsthrough the gears 27 and 28 to rotate the sprocket 3d; and acts throughthe gear train ll, 28, 32, 33, 35, 36, and 38 to rotate the sprocket 3!!in a direction opposite to the direction of rotation of the sprocket 30.The prism block 22, sprocket 30 and sprocket 3! are thus rotated insynchronism with one another and at such same rate of speed that therays passing through the block 22 are displaced downward at the rate atwhich the film l8 moves downward past the slot H9.

The shaft as has fixed thereto a pulley 39 which is connected by a belt30 with a pulley M which may be connected by a ball clutch 32 with ashaft 63 journalled in the film supply magazine M, or, when reverselyoperated, the pulley iii may be connected through the oppositely actingball clutch 435 with the shaft it journalled in the film take-upmagazine i'i. Consequently when the shaft 23 is rotated in one directionit acts through the parts described to rotate the shaft as carrying thefilm take-up roll, and when the shaft 23 is rotated in the oppositedirection it acts through the parts described to rotate the shaft 43.carrying the film supply roll.

The film magazines fi l and ll are each provided with a slot 448 (Fig.4) adapted to register with a slot 49 in the top of the camera. The slot18 is normally closed to light by a pair of shields 50 journalled on thestubs 5i and normally turned toward closed position by suitable springs.The edges of the shields 50 are preferably edged with velvet 53 orthe'like to better seal the joint between the shields or flaps 5!! whenthe latter are in closed position. Stubs 541 mounted in recesses in thebottom of the film magazines are, elevated by bosses 55 fixed in the topof the camera housing so as to open the flaps 5!! as the' film magazineis properly seated on the top of the camera housing.

The film of the supply roll 56 is drawn downward, between guide rollers51 and through the slots G8, 49, by the rotation of the sprocket 30against which the film is held by pressure rollers 58 and 59. It thenpasses downward over the idler roller 60 against which the film is heldby a spring roller 60', so that the film moves downward past the gateaperturetangentially to the periphery of the idler 60. After passingaroun the roller 68), the film moves upward and is again engaged againstthe sprocket 30 by pressure rollers 6i and 62, and on passing over thelatter the film is bent in a free loop as illustrated in Fig. 2 andpasses over the sprocket 3!, against i9 is recessed as at 66 to clear anopening 61 by which a light beam is projected against the 'lies in aplane tangent to the rollers 2,055,492 edge of the film from atriangular prism as to print a sound record thereon. A lens 69 in thetube 10 receives a beam of light through the slot 'H in the adjustabletube 12. The intensity of the beam passing through the slot II andconcentrated upon the edge of the film by means of the lens 69 and prism68 is varied by a photoelectric cell (not shown) or other suitable meansfor transforming sound waves into light rays so that a sound record andan image record are simultaneously made upon the film.

In the embodiment of my invention illustrated in Figs. and 6, the lenstube Illa is adjustably supported by the bracket Ila having thereon arack I30. meshing with the gear wheel Ma which may be operated by asuitable external knob to focus the photographic lens 9. The lens tubeIlia is connected with the partition 2 by an accordion member I2a. topermit the focusing of the lens 9 to form an aerial image substantiallyin the plane of the aperture IS in the partition 2. The auxiliary lensI! and rotatable prism 22a are mounted in the optical axis of the lens 9and project the image formed in the plane of the aperture l6 onto thefilm l8 as it passes the slot l9 between the. adjustable gate leaves I9controlling the image aperture 20 in the partition 3.

The film I 8 and prism block 22a are operated in synchronism so as totranslate aerial image formedwin the plane of the film at the rate, ofadvance of the film past the slot l9 by means of a crank handle 24connected with the shaft 23a journalled in the camera. housing andhaving thereon a worm 25!; which meshes with the gear 260; fixed on theshafts 2|a supporting the prism block 2211 through suitable cheekplates. The shaft 23a also has fixed thereon the worm 21a which mesheswith a gear wheel 28a fixed on the shaft 29:: of a toothed sprocket 30a.

The shaft 29a also has fixed thereto a pulley 39a which acts through thebelt 40a to rotate the pulley a on the shaft 46a journalled in the filmmagazine 41a and carrying the film take-up roll. The film supply roll ismounted on a shaft 430 in the supply magazine a. and is drawn by thesprocket 30a downward through slots 48 and 49, under the idler roller58a and over a toothed sprocket 30' on the shaft 28", the film beingpressed against the sprocket 30 by the idler roller 59a. The filmpassing the slot is or sprockets 30' and 30a, and is shielded by anapron 50a.

After passing the slot i9 and passing over the sprocket 30a the film iscarried upwardly between rollers Bio; and 62a. to a take-up spool on theshaft 460. in the magazine 41a.

When it is desired to reverse the movement of the film, the belt 40a isdisengaged from the pulleys 39a and a: and the crank handle 24 isdisengaged from the shaft 23a and engaged on a projecting shank of theshaft 28" of the sprocket 30'. The shaft 28" has fixed thereto a pulley350. which acts through a supplementary belt 36a to drive a pulley 38afixed on the shaft 43a of the film magazine a and which carries the filmsupply spool. 7

The sound recording mechanism illustrated in Figs. 8 and 9 is applicableto this embodiment of my invention in themanner described in connectionwith the first described form of camera, and the operation of the entireapparatus will be obvious from the description of operations heretoforegiven.

The embodiment of my invention illustrated in Fig. 7 diifers from thepreviously described apparatus only in the positioning of the prismblock 22b in the objective space instead of the image space of the lensl1.

By my novel combination and arrangements of a film carrier, displacingprism and lenses, I am enabled to reproduce an image generated by thephotographic lens and give such movement to the reproduction as accorwith the film movement, which when moved con inuously past a lightaperture passing but a fragment of the image receives a proper exposureand a continuously changing life-like imprint of the scene, andconcurrently therewith a complementary sound record substantially intransverse coincidence with the pertinent image. I am thus enabled toavoid in recording and reproducing the difliculties incident to makingor reproducing scene records during intermittent movements of a film andcomplementary sound records during prior or subsequent continuousmovements thereof.

Having described my invention, I claim:

1. In the method of producing chronophotographs, the steps which consistin continuously moving a sensitized strip, forming an aerial image, andforming a conjugate image of such aerial image, such conjugate imagebeing coincident with the plane of movement of the sensitized strip,sequentially photographing upon said moving sensitized strip fragmentaryportionsof said conjugate image, the light rays forming such conjugateimage being displaced each parallel to itself synchronously with themovement of said strip.

2. The method of producing chronophoto graphs which consists incontinuously moving a sensitized strip, subjecting sequential sectionsof said strip to the action of light rays from sequentially adjacentfragmentary portions of a scene until a complete image of the scene hasbeen photographed upon the sensitized strip, said strip beingcontinuously exposed to the action of light rays from said scene duringthe photographing of a complete image of the scene and continu ouslyrepeating such photographing of fragmentary portions of the scene toform a series of related images upon the strip, each of said relatedimages being maintained coaxially with said scene.

3. In motion picture apparatus with uniform film movement, thecombination with film feeding mechanism and a rotatable piano-parallelrectifying member synchronized with the feeding mechanism and having atleast two parallel surfaces, of a collective real image forming lenssystem having a focal plane coincident with the plane of movement of thefilm, and a gate between the rectifying member and the film plane andcontaining an aperture passing one after another parallel bands or rays,each band forming a portion only of the rays deflected at any one timeby said rectifier so as to pass through the aperture sequentially raysforming consecutive fragments of a unit image from each of said parallelbands.

4. In the method of producing chronophotographs, the steps which consistin continuously moving a sensitized strip, forming a real image of ascene, and sequentially photographing upon said sensitized strip aseries of complementary fragmentary portions, with parallel edges, ofsuch image, such complementary fragmentary por-

